Overactive bladder is a medical condition that affects more than 50 million people in the United States. Individuals with an overactive bladder typically experience an increase in urge and frequency of urination, and occasionally incontinence. An overactive bladder may result from increased triggering of the sensory pathways involved in normal bladder control. It has been suggested that abnormal bladder activity may result from morphological changes in one or more distinct anatomical areas of the bladder, including the dome, internal sphincter or trigone. For example, localized changes in detrusor muscle morphology resulting from defects at the cellular and multicellular level tend to correlate with pathological changes, e.g., patchy denervation due to increased amounts of connective tissue between muscle bundles, which may contribute to abnormal muscle function on a macroscopic level. These localized defects often manifest as elevated electrical activity within specific tissue regions of the bladder wall. Identifying and treating these localized defects may prevent or eliminate the symptoms of overactive bladder. Current treatments for overactive bladder, such as systemic administration of drugs, nerve stimulation or Botox injections, are applied to the entire bladder rather than specifically targeting local anatomical abnormalities. Because the therapeutic effect eventually wears off, these treatments often need to be repeated multiple times. Unfortunately, overtreatment may lead to urinary retention that requires self-catheterization to void the bladder.
The transient nature of these systemic treatments may be addressed by mapping the tissues of the bladder wall to identify where local bladder abnormalities originate and then specifically targeting therapeutic treatment to those areas. Currently available bladder mapping devices do not conform to the shape of the bladder and cannot reliably establish and/or maintain contact between each of the electrodes and the bladder wall. Proper positioning of the electrodes may be achieved by attaching the electrodes to the surface of a balloon, as described by Drake et al. (BJU International 2005, vol. 95, pp. 1002-1005). However, the interface between the outer surface of the balloon and the bladder wall leads to irritation of the bladder, which tends to result in artifactual electrical measurements.
There is a continued need for systems and methods for identifying local bladder abnormalities and specifically targeting therapeutic treatments to those areas in a minimally invasive manner. Such treatments may provide a permanent therapeutic effect without increasing the duration of the medical procedure.